Datasheet

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STM32F20xxx Functional overview
177
3.23 Serial peripheral interface (SPI)
The STM32F20x devices feature up to three SPIs in slave and master modes in full-duplex
and simplex communication modes. SPI1 can communicate at up to 30 Mbits/s, while SPI2
and SPI3 can communicate at up to 15 Mbit/s. The 3-bit prescaler gives 8 master mode
frequencies and the frame is configurable to 8 bits or 16 bits. The hardware CRC
generation/verification supports basic SD Card/MMC modes. All SPIs can be served by the
DMA controller.
The SPI interface can be configured to operate in TI mode for communications in master
mode and slave mode.
3.24 Inter-integrated sound (I
2
S)
Two standard I
2
S interfaces (multiplexed with SPI2 and SPI3) are available. They can
operate in master or slave mode, in half-duplex communication modes, and can be
configured to operate with a 16-/32-bit resolution as input or output channels. Audio
sampling frequencies from 8 kHz up to 192 kHz are supported. When either or both of the
I
2
S interfaces is/are configured in master mode, the master clock can be output to the
external DAC/CODEC at 256 times the sampling frequency.
All I2Sx interfaces can be served by the DMA controller.
3.25 SDIO
An SD/SDIO/MMC host interface is available, that supports MultiMediaCard System
Specification Version 4.2 in three different databus modes: 1-bit (default), 4-bit and 8-bit.
Table 6. USART feature comparison
USART
name
Standard
features
Modem
(RTS/CTS)
LIN
SPI
master
irDA
Smartcard
(ISO 7816)
Max. baud rate
in Mbit/s
(oversampling
by 16)
Max. baud rate
in Mbit/s
(oversampling
by 8)
APB
mapping
USART1 X X X X X X 1.87 7.5
APB2 (max.
60 MHz)
USART2 X X X X X X 1.87 3.75
APB1 (max.
30 MHz)
USART3 X X X X X X 1.87 3.75
APB1 (max.
30 MHz)
UART4 X - X - X - 1.87 3.75
APB1 (max.
30 MHz)
UART5 X - X - X - 3.75 3.75
APB1 (max.
30 MHz)
USART6 X X X X X X 3.75 7.5
APB2 (max.
60 MHz)